Implicit application of non‐reflective boundary conditions for Navier–Stokes equations in generalized coordinates

The non‐reflective boundary conditions (NRBC) for Navier–Stokes equations originally suggested by Poinsot and Lele (J. Comput. Phys. 1992; 101 :104–129) in Cartesian coordinates are extended to generalized coordinates. The characteristic form Navier–Stokes equations in conservative variables are given. In this characteristic‐based method, the NRBC is implicitly coupled with the Navier–Stokes flow solver and are solved simultaneously with the flow solver. The calculations are conducted for a subsonic vortex propagating flow and the steady and unsteady transonic inlet‐diffuser flows. The results indicate that the present method is accurate and robust, and the NRBC are essential for unsteady flow calculations. Copyright © 2005 John Wiley & Sons, Ltd.     

Triple positive solutions for a class of -point dynamic equations on time scales with -Laplacian

This paper deals with a class of second-order nonlinear m-point dynamic equation on time scales with one-dimensional p-Laplacian. Using a fixed point theorem for operators on a cone, we provide sufficient conditions for the existence of at least three positive solutions to the above boundary value problem. The interesting point is that the nonlinear term f is involved with the first-order delta derivative explicitly. Meanwhile, an example is worked out to demonstrate the main results.     

二元外代数的Z_n-Galois覆盖代数的Hochschild(上)同调群

设Λ是特征不整除n的域k上的二元外代数,■是Λ的Zn-Galois覆盖代数.首先构造了■的极小投射双模分解,并由此清晰地计算了■的各阶Hochschild同调和上同调群的维数;并且在域的特征为零时,计算了■的循环同调群的维数.     

The nucleophilic reaction of polyfluoroaromatic compounds: II. The nucleophilic cyclization of chloropentafluorobenzene

The results of cyclization reaction between chloropentafluorobenzene and bifunctional nucleophiles such as XCH₂CH₂OH(X=OH, NHMe, NHEt) and HN (CH₂CH₂OH)₂, NH₂CH₂CH₂NH₂ were reported. It was found that the NaH/DMF system was a better reagent for the preparation of sodium alcoholates and the yields of cyclic products ranged from 50–80% which were much higher than that reported by previous workers.³     

Theoretical thermochemistry: Entropies and heat capacities for organosilicon compounds part 3

Ab initio molecular orbital theory was used to compute entropies, heat capacities and other thermochemical properties for a new organosilicon compound H₂SiNaF in the temperature range 300–1500 K. There is currently no information of this kind available about this compound. On the basis of the calculated heat capacities, we have fitted the temperature-dependent functions for heat capacities to the forms (a+bT+cT²) and (a'+b'T+c'T^?2) in the range 300–1500 K. Furthermore, we calculated the equilibrium constants of conversions among the four configurations of this compound. Thus, a new way of determining thermodynamic data theoretically can be derived and is expected to be established.     

Experimentelle Bestimmung des Staupunktswärmeüberganges in Argon im Stoßwellenrohr

Zusammenfassung Es wird die Theorie der elektrisch isolierten Kalorimetersonde mit endlicher Schichtdicke entwickelt. Anhand des Ergebnisses lassen sich die möglichen Fehler der Sonde leicht abschätzen. Außerdem wird der Einfluß der Temperaturverteilung auf den Widerstand diskutiert. Die experimentellen Ergebnisse des Wärmeüberganges im Staupunkt einer Halbkugel in Argon und Luft werden befriedigend mit der Theorie vonFay undRiddell erklärt. Bisherige experimentelle Ergebnisse lagen entweder zu hoch oder zu niedrig.

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Experimental determination of the stagnation point heat transfer in argon in a shock tube

The theory of the electrically insulated calorimeter gauge with finite thickness has been developed. From the theoretical results the possible errors of the gauge can be estimated. The influence of the temperature distribution on the electrical resistance is given. The experimental results of the heat transfer to the stagnation point of a spherical cylinder in argon and air agree reasonably with the theory ofFay andRiddell. Earlier experimental results have been found too high or too low.

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Bezeichnungen (Verwendete Einheiten in Klammern) a=/c· Temperaturleitfähigkeit (cm²/s) - c spezifische Wärme (Ws/g grd) - d, L, B Längen (cm) - e=c Wärmeeindringzahl (Ws^1/2/cm² grd) - F Pläche (cm²) - I Strom (A) - M _s Stoß-Machzahl - q Wärmestromdichte (W/cm²) - R Widerstand () - t Zeit (s) - T Temperatur (°K, grd) - U Spannung (V) - x, y, z Raumkoordinaten (cm) - Temperaturkoeffizient des Widerstandes (grd^–1) - Wärmeleitfähigkeit (W/cm grd) - Dichte (g/cm³)     

高能不等核碰撞和弛豫时间的相对论动力论方程描述

本文用相对论动力论方程描述高能重离子碰撞时空演化,并用它分析在200A GeV的¹⁶O束流和³²S束流下,于快度中心区的末态粒子快度分布,确定了不同系统的弛豫时间.     

The reactions of perfluoroalkanesulfinates: II. A new method for the synthesis of N,N-bisperfluoroalkylhydroxylamine1

The reaction of sodium or silver perfluoroalkanesulfinate with nitric acid, nitrous acid or nitrogen dioxide in aqueuos solution gave a moderate yield of N, N-bisperfluoroalkylhydroxylamine accompanied by perfluorocarboxylic acid, amide and nitrosoperfluoroalkane.     

Synthesis and characterization of the first trimetallic nitride templated pyrrolidino endohedral metallofullerenes

New pyrrolidino derivatives of both diamagnetic and paramagnetic trimetallic nitride templated endohedral metallofullerenes were synthesized by the Prato reaction, isolated and characterized by means of MALDI-TOF MS, NMR and UV-vis spectroscopies.